GLUT4 Gene Expression Research Articles

Antidiabetic and anti-inflammatory effects of two Fabaceae extracts against streptozotocin induced diabetic impairment in male rats

The present study aimed to investigate the antidiabetic and anti-inflammatory effects of Trifolium alexandrinum (TA) and Trifolium Pretense (TP) against streptozotocin induced diabetic impairment in male rats. Forty adult Wistar albino male rats were divided into four groups: Group 1, Control; Group 2, streptozotocin (STZ); Group 3, STZ + TA –treated group and Group 4, STZ + TP–treated group. TA and TP showed a significant reduction in the blood glucose, glycosylated hemoglobin (Hb A1C) levels and elevation in insulin and C-peptide. They restored the glycogen content of liver and skeletal muscle, also showed improvements in the activities of α-amylase, carbohydrate metabolic enzymes, lipase and lipid profile. Treatment with TA and TP extracts resulted in an improvement of the oxidative parameters and enhancement in the antioxidant enzymes in the pancreas and liver. While, pancreatic TNF-α, IL-1β, IL-6, NO, iNos and caspase-3 levels were significantly reduced with the treatment of TA and TP extracts. Administration of TA and TP extracts to diabetic rats revealed elevation in the GLUT4 levels of the skeletal muscle and pancreas. They caused up regulation in pancreatic GLUT2 gene expression. TA and TP extracts showed signs of regeneration of β-cells and improvement in the pancreatic tissue. It could be concluded that TA and TP extracts possess antioxidant and hypoglycemic potential resulting in reduction of the elevated oxidative stress and pro-inflammatory cytokines.

Inhibition of the facilitative sugar transporters (GLUTs) by tea extracts and catechins.

Tea polyphenolics have been suggested to possess blood glucose lowering properties by inhibiting sugar transporters in the small intestine and improving insulin sensitivity. In this report, we studied the effects of teas and tea catechins on the small intestinal sugar transporters, SGLT1 and GLUTs (GLUT1, 2 and 5). Green tea extract (GT), oolong tea extract (OT), and black tea extract (BT) inhibited glucose uptake into the intestinal Caco-2 cells with GT being the most potent inhibitor (IC50 : 0.077mg/mL), followed by OT (IC50 : 0.136mg/mL) and BT (IC50 : 0.56mg/mL). GT and OT inhibition of glucose uptake was partial non-competitive, with an inhibitor constant (Ki ) = 0.0317 and 0.0571mg/mL, respectively, whereas BT was pure non-competitive, Ki =0.36mg/mL. Oocytes injected to express small intestinal GLUTs were inhibited by teas, but SGLT1 was not. Furthermore, catechins present in teas were the predominant inhibitor of glucose uptake into Caco-2 cells, and gallated catechins the most potent: CG > ECG > EGCG≥GCG when compared to the non-gallated catechins (C, EC, GC, and EGC). In Caco-2 cells, individual tea catechins reduced the SGLT1 gene, but not protein expression levels. In contrast, GLUT2 gene and protein expression levels were reduced after 2hours exposure to catechins but increased after 24hours. These in vitro studies suggest teas containing catechins may be useful dietary supplements capable of blunting postprandial glycaemia in humans, including those with or at risk to Type 2 diabetes mellitus.

MON-613 The Expression of TBC1 Domain Family, Member 4 (TBC1D4) in Skeletal Muscles of Insulin-Resistant Mice in Response to Sulforaphane

The Expression of TBC1 Domain Family, member 4 (TBC1D4) in Skeletal Muscles of Insulin-Resistant Mice in Response to Sulforaphane. Background: Obesity is commonly accompanied by impaired glucose homeostasis. Decreased glucose transport to the peripheral tissues, mainly skeletal muscle, leads to reduced total glucose disposal and hyperglycemia. TBC1D4 gene is involved in the trafficking of GLUT4 to the outer cell membrane in skeletal muscle. Sulforaphane (SFN) has been suggested as a new potential anti-diabetic compound acting by reducing blood glucose levels through mechanisms not fully understood (1). The aim of this study is to investigate the effects SFN on TBC1D4 and GLUT4 gene expression in skeletal muscles of DIO mice, in order to elucidate the mechanism(s) through which SFN improves glucose homeostasis. Methodology: C57BL/6 mice (n=20) were fed with a high fat diet (60%) for 16 weeks to generate diet induced obese (DIO) mice with body weights between 45–50 gm. Thereafter, DIO mice received either SFN (5mg/kg BW) (n=10) or vehicle (n=10) as controls daily by intraperitoneal injections for four weeks. Glucose tolerance test (1g/kg BW, IP) and insulin sensitivity test (ITT) were conducted (1 IU insulin/ g BW, IP route) at the beginning and end of the third week of the injection.At the end of 4 weeks of the injection, samples of blood and skeletal muscles of both hindlimbs were collected. The expression levels of GLUT4 and TBC1D4 genes were analyzed by qRT-PCR. Blood was also used for glucose, adiponectin and insulin measurements. Results: SFN-treated DIO mice had significantly lower non-fasting blood glucose levels than vehicle-treated mice (194.16 ± 14.12 vs. 147.44 ± 20.31 mg/dL, vehicle vs. SFN, p value=0.0003). Furthermore, GTT results indicate that the blood glucose levels at 120 minutes after glucose infusion in was (199.83±34.53 mg/dl vs. 138.55±221.78 mg/dl) for vehicle vs. SFN with p=0.0011 respectively. ITT showed that SFN treatment did not enhance insulin sensitivity in DIO mice. Additionally, SFN treatment did not significantly change the expression of TBC1D4, and GLUT4 genes in skeletal muscles compared to vehicle treatment (p values >0.05).Furthermore, SFN treatment did not significantly affect the systemic insulin (1.84±0.74 vs 1.54±0.55 ng/ml, p=0.436), or adiponectin (11.96 ±2.29 vs 14.4±3.33 ug/ml, p=0.551) levels in SFN vs. vehicle-treated DIO mice, respectively. Conclusion: SFN treatment improves glucose disposal in DIO mice, which is not linked to the gene expression of GLUT4 and TBC1D4 and its mechanism of glucose disposal in skeletal muscles. Furthermore, SFN treatment did not improve insulin level, and the insulin sensitizer hormone adiponectin as potential players for enhancing insulin sensitivity.1.Axelsson AS, Tubbs E, Mecham B, Chacko S, Nenonen HA, Tang Y, et al. Sci Transl Med. 2017;9(394).

MON-639 Melanocortin 4 Receptor Contributes to Glucose Homeostasis by Regulating Kidney Glucose Reabsorption via the Glucose Transporter GLUT2

Melanocortin 4 receptor (MC4R) is essential for normal body weight and food intake. Deficiency of MC4R causes obesity in humans and mice. While the function of MC4R is well established in appetite regulation, its direct role in glucose homeostasis is unclear. Humans and mice with MC4R deficiency exhibit hyperinsulinemia and insulin resistance; however, they remain protected from fasting hyperglycemia/diabetes. To determine the role of MC4R in glucose homeostasis, we performed oral glucose and intra-peritoneal insulin tolerance tests (OGTT / ITT) in male and female Mc4r knockout (KO) and wild type (WT) mice. Remarkably, Mc4r KO mice exhibited improved glucose tolerance compared to WT mice (Area under the curve for OGTT, male: 29,125±2,028 vs. 38,493±1,161 mg/dL.min; female: 36,322±1,100 vs. 49,539±1,911 mg/dL.min, p<0.0001). The improvement in glucose tolerance was despite insulin resistance in Mc4r KO mice (Plasma insulin, male: 9.9±1.7 vs. 0.7±0.1 ng/mL, female: 6.2±2.0 vs. 1.1±0.3 ng/mL, p<0.05; Area under the curve for ITT, male: 13,174±1,073 vs. 8,132±255 mg/dL.min; female: 13,927±1,253 vs. 7,506±267 mg/dL.min, p<0.01). Based on our previous findings from POMC deficient mice, we hypothesized that the improved glucose tolerance in the Mc4r KO mice is due to their elevated glycosuria (excretion of glucose in urine). To test this hypothesis, we challenged Mc4r KO and WT mice with oral glucose (250 mg) and collected their 24h urine to evaluate glycosuria. Indeed, the KO mice demonstrated elevated glycosuria compared to their WT littermates (Urine glucose, male: 284±48 vs. 0.4±0.03 mg/24h, female: 63.4±14 vs. 1±0.6 mg/24h, p<0.002). To assess molecular mechanisms underlying elevated glycosuria in Mc4r KO mice, we measured the gene expression and levels of the kidney glucose transporters GLUT1, GLUT2, SGLT1 and SGLT2. Glut2 mRNA was reduced by ~ 40% and the protein level was decreased by ~ 20% in Mc4r KO mice compared to their WT littermates. The other glucose transporters remained unchanged. Altogether, our study demonstrates that MC4R contributes to glucose homeostasis by regulating kidney glucose reabsorption via GLUT2. These findings may explain why MC4R deficient mice or humans remain protected from diabetes despite their longstanding obesity and insulin resistance.

The effects of mitochondrial dysfunction on energy metabolism switch by HIF-1α signalling in granulosa cells of polycystic ovary syndrome.

This study aimed to determine the effects of mitochondrial dysfunction on energy metabolism of granulosa cells (GCs) and the competence of oocytes in polycystic ovary syndrome (PCOS). A total of 107 patients who underwent controlled ovarian hyperstimulation (COH) were enrolled. The clinical outcomes of patients with and without PCOS under in vitro fertilisation-embryo transfer (IVF-ET) were compared. Human primary GCs were exposed to mitochondrial and glycolysis inhibitors. Then, the related indicators of mitochondrial activity and glycometabolism were compared with controls. The viability of GCs after mitochondrial inhibitors was also determined. In PCOS patients, the number of retrieved oocytes significantly increased, but the high-quality embryos, available embryos, and high-quality blastocyst formation obviously decreased (p < 0.05). Furthermore, the mitochondrial membrane potential, adenosine triphosphate (ATP) content, mitochondrial DNA (mtDNA) copy number, and HIF-1α mRNA levels in GCs decreased, while the levels of reactive oxygen species increased (p < 0.05). Mitochondrial inhibitors reduced the mitochondrial function, but increased the HIF-1α, GLUT1, LDHA, and PFKP gene expression. Glucose consumption gradually increased at 24, 48, and 72 hours of GC culture after CCCP treatment, and the viability of cells tested by CCK-8 increased (p < 0.05). GCs are dependent on mitochondrial respiration and glycolysis for energy provision. Mitochondrial dysfunction accompanied by abnormal glycolysis was observed in PCOS patients, which affects the switch of energy from metabolic to glycolytic. The failure of transformation to glycolysis and low HIF-1a expression in GCs during the development of follicles might be correlated with the low oocyte competence of PCOS.

Gene and immunohistochemical expression of HIF-1α, GLUT-1, FASN, and adipophilin in carcinoma ex pleomorphic adenoma development.

To analyze the gene and immunohistochemical expression of HIF-1α, GLUT-1, FASN, and adipophilin in normal salivary gland (NSG), pleomorphic adenoma (PA), and carcinoma ex pleomorphic adenoma (CXPA) samples. The gene expression was investigated by the real-time PCR (qRT-PCR) method in 9 samples of frozen tissues of normal salivary gland, 13 PA, and 10 CXPA. We validated the reactions by immunohistochemistry on 20 samples from NSG, 85 PA, and 44 CXPA. Our results showed that there was no statistically significant difference in HIF-1α gene and immunohistochemistry expression among the tissues studied while FASN gene and immunohistochemistry expression increased along the carcinogenesis of the PA. GLUT-1 was significantly more expressed in tumor tissues (PA and CXPA), although protein is mainly expressed in transformed cells than in PA and NSG. In contrast, adipophilin was significantly more expressed in NSG while the expression of the protein increased in PA and CXPA. In summary, the data presented here suggest that neoplastic cells reprogram the expression of GLUT-1 and adipophilin to adapt to the tumor microenvironment and reinforce, through immunohistochemical results, a possible transcriptional and post-translational regulatory mechanisms that act on the expression of these genes.

Glucose transporter 2 in common carp (Cyprinus carpio L.): molecular cloning, tissue expression, and the responsiveness to glucose, insulin, and glucagon.

Glucose transporter 2 (glut2) has been studied in mammals, aves, and several fish, while the comparative studies of glut2 in common carp are still lacking. In this study, glut2 was firstly isolated and characterized from the liver of common carp. The full-length cDNA of glut2 was 2351bp with an open reading frame (ORF) of 1512bp, encoding 503 amino acids. Alignment of glut2 amino acid sequences from different species revealed that common carp glut2 showed higher sequence identity with teleosts, and lower homology with mammals and amphibians. Tissue distribution demonstrated that glut2 mRNA level was mainly expressed in liver, foregut, and midgut. To investigate the actions of glut2 on glucose metabolism, the level of glut2 mRNA was detected after intraperitoneal injection of glucose, human insulin and glucagon (100ng/g), respectively. Following glucose administration, glut2 gene expression was significantly upregulated at 3h in the foregut. However, no change was found in hepatic glut2 mRNA level, indicating that glut2 may have a role in intestinal glucose uptake rather than in the liver. Following insulin treatment, the expression of glut2 was markedly downregulated at 3h and 6h in the liver, and at 3h in the foregut, respectively. Furthermore, glut2 mRNA expression was unaffected by glucagon injection in the liver and foregut. These results suggested that the expression of glut2 regulated by pancreatic hormones was different. Taken together, our studies firstly revealed the structure of the glut2 gene and its potential functions in glucose metabolism of common carp.

Impact of diets rich in olive oil, palm oil or lard on myokine expression in rats.

It has recently emerged that myokines may be an important skeletal muscle adaptive response to obesogenic diets in sedentary subjects (who do not exercise). This study aimed to assess the influence of various high fat (HF) diets rich in either crude palm oil (cPO), refined palm oil (rPO), olive oil (OO) or lard on the modulation of myokine gene expression in the gastrocnemius. Five groups of 8 rats were each fed HF or control diet for 12 weeks. Systemic parameters concerning glucose, insulin, inflammation, cholesterol, triglycerides (TG) and transaminases were assessed by routine methods or ELISA. Akt and ACC phosphorylation were analyzed by WB in the soleus. Mitochondrial density, inflammation, and the gene expression of 17 myokines and the apelin receptor (Apj) were assessed by qPCR in the gastrocnemius. We found that HF diet-fed rats were insulin resistant and Akt phosphorylation decreased in the soleus muscle, but without any change in Glut4 gene expression. Systemic (IL-6) and muscle inflammation (NFκB and IκB) were not affected by the HF diets as well as TBARS, and ASAT level was enhanced with OO diet. Soleus pACC phosphorylation and gastrocnemius mitochondrial density were not significantly altered. The gene expression of some myokines was respectively increased (myostatin and Il-15) and decreased (Fndc5 and apelin) with the HF diets, whatever the type of fat used. The gene expression of two myokines with anti-inflammatory properties, Il-10 and myonectin, was dependent on the type of fat used and was most increased respectively with cPO or both rPO and OO diets. In conclusion, high-fat diets can differentially modulate the expression of some myokines, either in a dependent manner or independently of their composition.

Changes in Maternal Lifestyle during Ramadan Altered Placental Development

People born with low birth weight are at a greater risk of developing later life diseases such as hypertension, diabetes and cancer. Recent studies have pinpointed the placenta as a critical factor involved in developmental programming. Changes in maternal lifestyle or dietary habits can alter placental development and increase the risk of developmental programming of adult diseases. Saudi people, including pregnant women, change their lifestyle and eating habits during the holy month of Ramadan. Previous studies found that the exposure to Ramadan lifestyle reduces placental weight; however, effects on other placental aspects remained unknown. We aimed to further examine the effects of exposure to Ramadan lifestyle on full-term placental morphometrics, histology and gene expression of key glucose transporters. To examine this, fresh placentas were collected from 60 healthy Saudi women. Samples were equally classified into two groups; not exposed to Ramadan lifestyle (control) or exposed to Ramadan lifestyle in the first. Placental weight, length and breadth were recorded and placental surface area was calculated. Placental tissue was processed and stained with eosin and hematoxylin for histological examination. Apoptosis was assessed using TUNEL assay. The gene expression of the glucose transporters GLUT1 and GLUT3 was evaluated. The results show that women exposed to Ramadan lifestyle have more elongated placentas with less central cord insertion. Placental weight and surface area were significantly lowered in women exposed to Ramadan lifestyle. Placental length was not affected but the breadth was significantly smaller in than control. Placentas exposed to Ramadan lifestyle had fewer and less-developed syncytial knots and thicker syncytiotrophoblast cells. Apoptosis was detected in placentas exposed to Ramadan lifestyle. GLUT1 mRNA expression was unaltered, but GLUT3 was increased compared to control group. These findings suggest that changes in maternal lifestyle during Ramadan can alter placental structure at morphometric, histological and molecular levels. These structural changes are indication of placental adaptations for a suboptimal maternal environment. Such adaptations have been linked to adult diseases in various populations worldwide. Further studies are required to evaluate the possible link between exposure to Ramadan lifestyle and the risk of developing adulthood chronic diseases in the Saudi population.

Isolation and Characterization of Mesenchymal Stem Cells from Human Gingiva

A new nonimmortalized cell line (MSC-GING) was isolated from the gingiva of a 35-year-old healthy donor and characterized. The analysis of different properties was carried out at the 6th, 7th, 13th, 18th, 20th, and 23rd passages. During long-term cultivation, the proportion of aging cells according to the activity of β-galactosidase increased. The cloning efficiency of MSC-GING cells was significantly reduced, and the number of aging β-galactosidase-positive cells was gradually increased during cell prolonged cultivation. Growth curves showed active cell proliferation at the sixth passage. It was significantly declined by the 18th and 20th passages. Karyotypic analysis at the 7th and 18th passages showed the presence of a diploid number of chromosomes (46) in metaphase plates. At passage 7, however, the proportion of cells with a normal diploid karyotype 46, XX, was 50 ± 5%. Other cells had a clonal rearrangement inv (10) (q21.1q25.1), an inversion of the long arm of chromosome 10. Their number significantly decreased during cultivation up to passage 18, while the proportion of cells with a normal diploid karyotype increased. The cell number with surface antigens common for human mesenchymal stem cells (CD44, CD73, CD90, CD105, HLA-ABC) and vimentin was high at passages 6 and 20, while CD34, CD45, and HLA-DR positive cells were very rare. It is noteworthy that no cells carrying markers of undifferentiated embryonic stem cells (Oct-4, SSEA-4, and SOX2) are observed at passages 6 and 20. It was shown that MSC-GING cells were able to differentiate in osteogenic and chondrogenic directions. The ability to differentiate in the adipogenic direction was manifested only at the level of glut4 gene expression. Induction of neuronal differentiation increased the expression the nse gene (neurospecific elonase). In general, the results confirmed the MSC status for the obtained line, but revealed significant karyotypic instability in the early passages, which decreased during the replicative aging.

Impact of curcumin treatment on diabetic albino rats.

The current study was aimed to study the effect of curcumin on the expression levels of brain glucose transporter 1 protein (GLUT1) and femoral muscle glucose transporter 4 protein (GLUT4), in addition to study its possible therapeutic role in ameliorating insulin resistance and the metabolic disturbance in the obese and type 2 diabetic male albino Wistar rat model. Diabetes was induced by a high-fat (HF) diet with low dose streptozotocin (STZ). Curcumin was administered intragastrically for 8 weeks (80 mg/kg BW/day). The HF-diet group developed obesity, hyperglycemia, hyperinsulinemia, reduced liver glycogen content with significant dyslipidemia. In the diabetic control group, hyperglycemia and insulin resistance high calculated homeostasis model assessment (HOMA-IR-index score) were pronounced, with reductions in liver and muscle glycogen contents, concomitant with dyslipidemia and significantly elevated malondialdehyde levels in liver and pancreas. GLUT1 and GLUT4 were down-regulated in the obese and the diabetic control groups, respectively. Curcumin, showed glucose-lowering effect and decreased insulin resistance, dyslipidemia and malondialdehyde levels in both tissues, it increased liver & muscle glycogen contents, compared to the diabetic control. Curcumin significantly up-regulated GLUT4 gene expression, compared to the diabetic control group. In conclusions, these results indicate a therapeutic role of curcumin in improving the diabetic status, obesity and enhancing the expression of GLUT4 gene.

Inhibition of JAK-STAT and NF-κB signalling systems could be a novel therapeutic target against insulin resistance and type 2 diabetes

AimsChronic inflammation is associated with the production of high levels of proinflammatory cytokines via the JAK-STAT and NF-κB signalling pathways which are known to be inhibited by tofacitinib and aspirin respectively. High levels of these cytokines increase the synthesis of suppressors of cytokines (SOCS), which at high levels inhibit insulin signalling leading to insulin resistance. The effects of tofacitinib and aspirin on the degree of insulin resistance in type 2 diabetic rats were determined. Materials and methodsRats were induced with type 2 diabetes (T2D) by administration of 10% fructose solution (ad libitum) followed by streptozotocin injection (40 mg/kg BW) and treated with different doses of tofacitinib (10 and 20 mg/kg BW), aspirin (100 and 200 mg/kg BW) and combination of the two drugs at both doses for 9 weeks. Key findingsResults showed that separate treatment with 10 mg/kg BW tofacitinib and 100 mg/kg BW aspirin significantly (P < 0.05) decreased tumour necrosis factor-α (TNF-α), interleukin 6 (IL-6) and serum amyloid A when compared to diabetic untreated rats. However, the combined therapy (10 mg/kg BW tofacitinib and 100 mg/kg BW aspirin) significantly decreased the levels of TNF-α, IL-6, serum amyloid A, HOMA-IR, blood glucose level and SOC-3 gene expression but significantly (P < 0.05) improved glucose homoestasis, insulin secretion, HOMA-β and GLUT-4 gene expression when compared to diabetic untreated rat. ConclusionIt was concluded that simultaneous inhibition of the JAK-STAT and NF-κB signalling pathways with tofacitinib and aspirin respectively, could mitigate insulin resistance and hyperglycemia in T2D.

Metabolic Remodeling in the Pressure-Loaded Right Ventricle: Shifts in Glucose and Fatty Acid Metabolism-A Systematic Review and Meta-Analysis.

BackgroundRight ventricular (RV) failure because of chronic pressure load is an important determinant of outcome in pulmonary hypertension. Progression towards RV failure is characterized by diastolic dysfunction, fibrosis and metabolic dysregulation. Metabolic modulation has been suggested as therapeutic option, yet, metabolic dysregulation may have various faces in different experimental models and disease severity. In this systematic review and meta‐analysis, we aimed to identify metabolic changes in the pressure loaded RV and formulate recommendations required to optimize translation between animal models and human disease.Methods and ResultsMedline and EMBASE were searched to identify original studies describing cardiac metabolic variables in the pressure loaded RV. We identified mostly rat‐models, inducing pressure load by hypoxia, Sugen‐hypoxia, monocrotaline (MCT), pulmonary artery banding (PAB) or strain (fawn hooded rats, FHR), and human studies. Meta‐analysis revealed increased Hedges’ g (effect size) of the gene expression of GLUT1 and HK1 and glycolytic flux. The expression of MCAD was uniformly decreased. Mitochondrial respiratory capacity and fatty acid uptake varied considerably between studies, yet there was a model effect in carbohydrate respiratory capacity in MCT‐rats.ConclusionsThis systematic review and meta‐analysis on metabolic remodeling in the pressure‐loaded RV showed a consistent increase in glucose uptake and glycolysis, strongly suggest a downregulation of beta‐oxidation, and showed divergent and model‐specific changes regarding fatty acid uptake and oxidative metabolism. To translate metabolic results from animal models to human disease, more extensive characterization, including function, and uniformity in methodology and studied variables, will be required.

Regulation of metabolism during hibernation in brown bears (Ursus arctos): Involvement of cortisol, PGC-1α and AMPK in adipose tissue and skeletal muscle

The purpose of this study was to investigate changes in expression of known cellular regulators of metabolism during hyperphagia (Sept) and hibernation (Jan) in skeletal muscle and adipose tissue of brown bears and determine whether signaling molecules and transcription factors known to respond to changes in cellular energy state are involved in the regulation of these metabolic adaptations. During hibernation, serum levels of cortisol, glycerol, and triglycerides were elevated, and protein expression and activation of AMPK in skeletal muscle and adipose tissue were reduced. mRNA expression of the co-activator PGC-1α was reduced in all tissues in hibernation whereas mRNA expression of the transcription factor PPAR-α was reduced in the vastus lateralis muscle and adipose tissue only. During hibernation, gene expression of ATGL and CD36 was not altered; however, HSL gene expression was reduced in adipose tissue. During hibernation gene expression of the lipogenic enzyme DGAT in all tissues and the expression of the FA oxidative enzyme LCAD in the vastus lateralis muscle were reduced. Gene and protein expression of the glucose transporter GLUT4 was decreased in adipose tissue in hibernation. Our data suggest that high cortisol levels are a key adaptation during hibernation and link cortisol to a reduced activation of the AMPK/PGC-1α/PPAR-α axis in the regulation of metabolism in skeletal muscle and adipose tissue. Moreover, our results indicate that during this phase of hibernation at a time when metabolic rate is significantly reduced metabolic adaptations in peripheral tissues seek to limit the detrimental effects of unduly large energy dissipation.

Effects of Chromium-Loaded Chitosan Nanoparticles on the Intestinal Electrophysiological Indices and Glucose Transporters in Broilers.

Simple SummaryChromium is an important trace element responsible for the metabolism of glucose by enhancing insulin activity. This study was planned to evaluate the effects of chromium-loaded chitosan nanoparticles on the transport of glucose or amino acid across jejunum, gene expression of glucose transporters, and glycogen contents of liver and muscle. The results revealed that an increase in the supplemented dose of chromium-loaded chitosan nanoparticles decreased liver glycogen content and glucose transport across jejunum, while the muscle glycogen, gene expression of glucose transporters, and amino acid transport remained unaffected.The present study aimed to evaluate the effect of chromium-loaded chitosan nanoparticles (Cr-CNPs) on the electrophysiological indices, gene expression of glucose transporters, and tissue glycogen in broilers. A total of 200 one-day-old broilers were randomly divided into five groups, with each having five replicates (n = 8). Group A was fed a corn–soybean meal diet, while the diets of groups B, C, D, and E were supplemented with 200, 400, 800, and 1200 µg/kg of Cr as Cr-CNPs, respectively. On day 35, the jejunum was collected for electrophysiological study, gene expression of glucose transporters, and tissues glycogen determination. The basal short-circuit current and tissue conductance before the addition of glucose was the same in all groups. Following the addition of glucose, the change in short-circuit current decreased (p < 0.05) in the jejunal tissues of birds supplemented with 400 and 1200 µg Cr-CNPs compared with the control group. Gene expression of SGLT-1 and GLUT-2 remained unaffected with supplementation. The serum glucose and liver glycogen concentration decreased (p < 0.05) linearly with supplementation, while no effect was observed on muscle glycogen. In conclusion, Cr-CNPs supplementation decreases the glucose absorption and liver glycogen content, without affecting the gene expression of glucose transporters.

Selective Accumulation of Galactomannan Amphiphilic Nanomaterials in Pediatric Solid Tumor Xenografts Correlates with GLUT1 Gene Expression.

In this work, we designed, characterized, and investigated the performance of hydrolyzed galactomannan (hGM)-based amphiphilic nanoparticles for selective intratumoral accumulation in pediatric patient-derived sarcomas. To create a self-assembly amphiphilic copolymer, the side chain of hGM was hydrophobized with poly(methyl methacrylate) (PMMA) by utilizing a graft free radical polymerization reaction. Different hGM and MMA weight feeding ratios were used to adjust the critical aggregation concentration and the size and size distribution of the nanoparticles. The ability to actively target glucose transporter-1 (GLUT-1) was studied by fluorescence confocal microscopy and imaging flow cytometry in vitro on Rh30 (rhabdomyosarcoma) and patient-derived Ewing sarcoma (HSJD-ES-001) cell lines with different expression levels of GLUT-1. Results confirmed that the nanoparticles are internalized by ∼100% of the cells at 37 °C. Furthermore, we investigated the biodistribution of the nanoparticles in pediatric patient-derived models of two deadly musculoskeletal tumors, rhabdomyosarcoma and Ewing sarcoma. Outstandingly, the intratumoral accumulation of the nanoparticles correlated very well with the expression level of GLUT1 gene in each patient-derived tumor (P = 0.0141; Pearson's correlation test). Finally, we demonstrated the encapsulation capacity of these nanoparticles by loading 7.5% (w/w) of the hydrophobic first-generation tyrosine kinase inhibitor imatinib. These findings point out the potential of this new type of nanoparticle to target GLUT-1-expressing tumors and selectively deliver anticancer agents.

Analysis of the Expression of Genes Related to Lipidic and Glycogenic Metabolism in Pleomorphic Adenomas and Carcinomas Ex Pleomorphic Adenomas

Abstract Introduction The carcinoma ex pleomorphic adenoma (CXPA) arises from a pleomorphic adenoma (PA) and is supposed to gain lipogenesis and glycogenesis during its malignant transformation. Increased lipogenesis is a characteristic of cancer cells, consisting of increased fatty acid synthesis by the enzyme fatty acid synthase (FASN) and by the accumulation of cytoplasmic lipid droplets, which express adipophilin. The increase in glycolytic metabolism has been associated with the activity of glycolytic enzymes and glucose transporters (GLUTs), whose expression is induced by HIF-1 (inducing factor of hypoxia 1). Objectives To analyze the gene expression of FASN, adipophilin, HIF-1α, and GLUT-1 in PA and CXPA samples. Methodology Gene expression analysis of the FASN, adipophilin, HIF1-α, and GLUT-1 genes was performed by the real-time PCR (qPCR) method. Fourteen cases of PA and 14 cases of CXAP were evaluated. Results FASN, adipophilin, HIF-1α, and GLUT-1 were more expressed in CXAP than in AP, although there was no significant difference between levels of adipophilin expression in CXPA and PA. Conclusion Increased expression of FASN, HIF1-α, and GLUT-1 in CXAP may be associated with malignant transformation of PA, while additional studies are needed to understand the role of adipophilin in PA carcinogenesis. Moreover, this is the first study to investigate the role of these genes in the malignant transformation of PA.

β-Catenin/Tcf7l2-dependent transcriptional regulation of GLUT1 gene expression by Zic family proteins in colon cancer.

The zinc finger of the cerebellum (ZIC) proteins has been implicated to function in normal tissue development. Recent studies have described the critical functions of Zic proteins in cancers and the potential tumor-suppressive functions in colon cancer development and progression. To elucidate the functional roles of Zic proteins in colorectal cancer, we knocked out the Zic5 gene and analyzed the chromatin localization pattern and transcriptional regulation of target gene expression. We found that Zic5 regulates glucose metabolism, and Zic5 knockout is accompanied by an increased glycolytic state and tolerance to a low-glucose condition. Furthermore, loss of β-catenin or TCF7l2 diminishes the chromatin binding of Zic5 globally. Our studies suggest that the Wnt/β-catenin signaling pathway has a strong influence on the function of Zic proteins and glucose metabolism in colorectal cancers through GLUT1. Interfering Wnt/-catenin-Zic5 axis-regulated aerobic glycolysis represents a potentially effective strategy to selectively target colon cancer cells.

Trans-fatty acids aggravate anabolic steroid-induced metabolic disturbances and differential gene expression in muscle, pancreas and adipose tissue

AimsAlthough anabolic steroids (AS) and trans-fatty acids overload exerts systemic toxicity and are independent risk factors for metabolic and cardiovascular disorders, their interaction remains poorly understood. Thus, we investigated the impact of a diet rich in trans-fatty acids (HFD) combined with AS on glycemic control, lipid profile, adipose tissue, skeletal muscle and pancreas microstructure and expression of genes involved in energy metabolism. Main methodsForty-eight C57BL/6 mice were randomized into 6 groups treated for 12 weeks with a standard diet (SD) or a diet rich in C18:1 trans-fatty isomers (HFD), alone or combined with 10 or 20 mg/kg testosterone cypionate (AS). Key findingsOur results indicated that AS improved glycemic control, upregulated gene expression of Glut-4 and CPT-1 in skeletal muscle, FAS, ACC and UCP-1 in adipose tissue. AS also reduced total and LDL cholesterol in mice fed a SD. When combined with the HFD, AS was unable to induce microstructural adaptations in adipose tissue, pancreatic islets and β-cells, but potentiated GCK and Glut-2 (pancreas) and Glut-4 and CPT-1 (skeletal muscle) upregulation. HFD plus AS also downregulated FAS and ACC gene expression in adipose tissue. Combined with HFD, AS increased triacylglycerol circulating levels, improved insulin sensitivity and glycemic control in mice. SignificanceOur findings indicated that HFD and AS can interact to modulates glycemic control and lipid profile by a mechanism potentially related with a reprogramming of genes expression in organs such as the pancreas, adipose tissue and skeletal muscle.

Ligand docking suggests isomer specific catechin induced SIRT‐1 activation

Cinnamon has been proposed to have multiple metabolic effects ranging from anti‐hyperglycemic effects to regulation of basal metabolic rates. Polyphenols such as resveratrol, caffeic acid, aspalathin, and quercetin have been shown to have similar effects through various pathways. Cinnamon extract contains many polyphenolic compounds with structural similarities to the studied polyphenols and as such may exhibit effects via the same biochemical pathways. Cinnamon extract contains a number of catechin isomers, polyphenolic molecules closely related to those stated previously. Due to these similarities, we propose that catechin may act through the pathways proposed for other polyphenols. Resveratrol has been shown to exert effects through modulation of SIRT‐1, a deacetylase enzyme involved in chromatin remodeling and control of gene expression. Our research primarily involved docking of the four catechin isomers into the allosteric binding site of the SIRT‐1 enzyme that resveratrol has been shown to act through. The two R isomers, (−)‐epicatechin (2R,3R) and (+)‐catechin (2R,3S), did not align with our assigned baseline values. However, these molecules cannot be ruled out for biological activity. The two S isomers of catechin, (−)‐catechin (2S,3R) and (+)‐epicatechin (2S,3S), showed favorable scores and positioning similarity to resveratrol. It was also observed through cooperative binding studies that (+)‐epicatechin (2S,3S) has the potential to be an activator of SIRT‐1. Other possible mechanisms of catechin include those of the other polyphenolic compounds. Quercetin has been shown to have effects via two major mechanisms. The first is by promoting glucose uptake in liver cells via upregulation of GLUT‐2 and GLUT‐4 gene expression. The other pathway involves down‐regulation of GLUT‐2 in intestinal microvilli to decrease absorption. Finally the effects of aspalathin have been shown to regulate GLUT‐4 translocation to the plasma membrane in L6 myocytes.Support or Funding InformationDepartment of Pharmaceutical and Biomedical Sciences, Raabe College of Pharmacy, Ohio Northern UniversityThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.